Question;
1) The function is increasing for all real values of x where
x < –4.
2) The function is increasing for all real values of x where
–6 < x < –2.
3) The function is decreasing for all real values of x where
x < –6 and where x > –2.
4) The function is decreasing for all real values of x where
x < –4.
Answer:
The correct option is;
1) The function is increasing for all real values of x where x < -4
Step-by-step explanation:
From the question we note that the vertex of the open down parabolic function f(x) = -(x+6)(x+2) is (-4, 4) with x intercept at (-2, 0)
Therefore, since the parabola is symmetric about the vertex, the other x intercept is (-6, 0)
The highest point of the function of the open down (turned, upside down) parabola is the vertex (-4, 4), also, a function is said to be increasing when the y value increases as the x value is increased
Points, f(x) values on the left of the vertex of an opened down parabola are increasing and points on the right are decreasing.
Therefore, since coordinates of points on the left of the vertex are that of x < -4, we have
The function is increasing for all real values of x where x < -4